1. Field of the Invention
This invention relates to novel cross-linkable, hydroxyl group-containing polymer resins which are produced by copolymerization from olefinically-unsaturated monomers with the simultaneous use of unsaturated C.sub.4 -diols or particular derivatives of such diols, and to the use of the polymer resins as binders for coating agents.
2. Description of the Prior Art
Hydroxyl group-containing polymer resins based on olefinically-unsaturated monomers and their use as binders for coating agents are described in a large number of publications (c.f. e.g. DE-OS No. 2,460,329, DE-AS No. 1,038,754, U.S. Pat. Nos. 3,002,959, 3,375,227, GB-PS No. 1,515,868).
These known hydroxyl group-containing polymer resins are particularly suitable in conjunction with organic polyisocyanates for the production of coatings having good mechanical qualities.
However, disadvantages of these coatings include their somewhat unsatisfactory weathering properties and the often inadequate resistance to organic solvents and aqueous bases. Thus, for example, finishing lacquer coatings for automobiles which are based on the above hydroxyl group-containing polymers, more particularly metal-effect multilayered lacquer coatings, the final covering layer of which contains metal pigments, often have only insufficient resistance to UV-light, which, in very sunny areas, can result in the formation of cracks. When these are clear lacquers based on the above polymers, they have a tendency to matt under the effects of weathering, thereby making unsightly the metal-effect lacquer coatings which have clear lacquers of this type as finishing lacquer.
Thus, an object of the present invention is to provide new binders which combine the advantages of known hydroxyl group-containing polymer resins without suffering the disadvantages thereof, that is to say binders which are particularly suitable for the production of weather and chemical-resistant coatings.
This object is achieved by providing the polymer resins according to the present invention, described in more detail in the following.